We are constantly learning new things about our climate. That was true before industrialized society started pumping out unprecedented amounts of greenhouse gases (GHGs), and it’s doubly true now as our climate is changing (in large part thanks to those aforementioned GHGs). A study published this week reveals an interesting quirk of climate change: it’s making snow melt sooner in the year, but that snow is actually melting slower than it used to. The AP reports:

Scientists have long known the annual snowmelt is starting sooner as the climate warms. New research by the National Center for Atmospheric Research in Boulder, Colorado, found that when the snow begins to melt earlier in the season, it dissipates more slowly than it does in late spring or summer, in part because the angle of the early year sun is lower so its rays are less intense.

The sun’s intensity is particularly important because the energy in direct sunlight is the biggest driver of snowmelt, said Keith Musselman, the lead researcher. Another factor that slows the snowmelt in the early season is the fact that nights are still cooler.

The conclusions, published in the journal Nature Climate Change, could help explain why computer models show rivers fed by mountain snow are expected to run lower in a warming climate, even if rainfall increases as snowfall decreases, said Musselman, a post-doctoral fellow at the Boulder research center.

The study itself didn’t say much about the broader implications of this new phenomenon, but the lead researcher pointed out that a slowdown in snowmelt could end up being used by plants or evaporating before making its way into rivers. That could spell big trouble for parts of the world where people rely on this annual meltwater for human consumption (in one form or another).

Those effects certainly deserve further scrutiny, but for the time being let’s focus on the fact that now, in February 2017, we are learning surprising and in some ways counterintuitive components of the immensely complex system that is our planet’s climate. There are so many variables to account for here, and even more interrelationships between those variables. The fact that snow melting earlier in the year might melt slower because it’s getting less direct sunlight is a perfect example of this complexity, and it’s a reminder to us all of just how difficult it is to get a firm grasp on this subject.

So yes, we can acknowledge that GHGs are leading to rising surface temperatures, and that humans are partly culpable for that, but those that claim that this entire field of science is somehow “settled” (looking at you, greens) only set themselves up to look foolish when study after study comes out refining our understanding of our climate. Over-confident environmentalists have made it a habit to exaggerate the confidence researchers have in modeling and predicting what comes next for climate change, and in so doing they’ve not only made themselves look foolish, they’ve made climate deniers out of plenty of skeptical people.